1 Field of the Invention
The present invention relates to a printing plate discharging method and printing plate discharging device for discharging a printing plate that is laid on a surface plate from the surface plate such as an exposure stage.
2 Description of the Related Art
Technology for printing plate automatic exposure devices has been developed whereby an image is recorded onto a printing plate. The printing plate (e.g. a PS plate, a thermal plate, a photopolymer plate, and the like) is provided with a recording layer on top of a base layer. The image is recorded at the printing plate""s recording layer with a direct laser beam or the like.
In this sort of technology, a plurality of printing plates are stored in a stacked state in a magazine beforehand. The printing plates are automatically taken one at a time and fed into an exposure section. At the exposure section, the printing plate that has been fed is placed on a surface plate in a state wherein one end of the printing plate is projecting, such that a puncher can punch holes for positioning at the end portion of the printing plate. The printing plate, which has been placed on the surface plate in the state wherein one end of the printing plate is projecting, is scanned and exposed by a scanning device under the same state. After the image has been exposed, the printing plate is discharged from the surface plate and sent to a developing device for a next process.
Images can be recorded onto printing plates quickly. Therefore, it is important that a printing plate that has been exposed on the surface plate is quickly and reliably discharged from the surface plate and fed to the next process. Conventionally, an exposed printing plate is discharged from the surface plate and fed to the next process by a plurality of transport rollers.
However, in this conventional discharging method of discharging the printing plate by means of transport rollers, a plate face of the printing plate (an exposed face) can easily become dirty or be scratched. Further, a transport mechanism for the plurality of transport rollers is relatively complicated and expensive. Therefore, an alternative is desired.
In view of the aforementioned, an object of the present invention is to provide a printing plate discharging method and printing plate discharging device that can quickly and reliably discharge a printing plate that is laid on a surface plate from the surface plate without making the exposed face of the printing plate dirty or scratched.
A first aspect of the present invention is a device for discharging a printing plate from a face of a surface plate having a back end portion, the device comprising: (a) a lifting member having a printing plate supporting portion that is movable up and down relative to a face of a surface plate, such that when said printing plate supporting portion moves to a position higher than the face of the surface plate, said printing plate supporting portion lifts a back end portion of the printing plate from the face of the surface plate to a position higher than the face of the surface plate; (b) a cam mechanism provided at said lifting member which moves said lifting member up and down; and (c) a discharging member disposed along the surface plate, the discharging member being movable from the back end portion of the surface plate to a front end portion of the surface plate while holding the back end portion of the printing plate which has been lifted by said lifting member, for discharging the printing plate from the face of the surface plate.
In the printing plate discharging device of the first aspect, the printing plate supporting portion of the lifting member is moved up and down by operation of a cam mechanism. Thus, the back end portion of the printing plate is temporarily raised to the position higher than the surface of the surface plate. The raised back end portion is engaged by the discharging member, pushed in an engaged state toward the front end portion of the surface plate, and discharged from the surface plate.
A second aspect of the present invention is a method for discharging a printing plate from a face of a surface plate, comprising the steps of: (a) raising a back end portion of the printing plate to a position higher than the face of the surface plate with a printing plate supporting portion of a lifting member; (b) holding the raised back end portion with an discharging member; and (c) discharging the printing plate from the face of the surface plate by moving said discharging member from a back end portion of the face of the surface plate to a front end portion of the face of the surface plate, while said discharging member holds the back end portion of the printing plate.
In the printing plate discharging method of the second aspect, the back end portion of the printing plate is temporarily raised to the position higher than the surface of the surface plate. The raised back end portion is engaged, pushed in an engaged state toward the front end portion of the surface plate, and discharged from the surface plate.
Hence, in the printing plate discharging device and printing plate discharging method of the present invention, only the back end portion of the printing plate is held when the printing plate is discharged. Thus, a printing surface of the printing plate (the exposed face) is less susceptible to becoming dirty or scratched. Further, the structure is simple: the back end of the printing plate, which back end is protruding from the surface plate, is simply raised to a position higher than the printing plate and then engaged and pushed. Therefore, the structure can be implemented without complicated and expensive mechanisms (devices). The printing plate that is laid on the surface plate can be quickly and reliably discharged from on the surface plate without making the exposed face dirty or scratched.